I believe it's the monthly allowance provided by a parent to their child who isn't yet working. After completing high school, the typical path leads to university. This means that the $100 covers their food and leisure expenses for one month, usually excluding tuition costs. CMIIW.

I agree with your statement that when buying Bitcoin, one should not expect substantial profits in the short term. Remember that everyone needs a considerable amount of time to reap profits because the process is not easy. Learning about crypto while practicing DCA is the best approach until OP can stand on your own and expand your crypto portfolio with earnings from your job. At least, with more funds, OP have clear goals and a basic knowledge of Bitcoin investment. This way, the journey with Bitcoin can become more seasoned and experienced.